RuntimeError: Unable to compute the rank, hence generators, with certainty (lower bound=0, generators found=[]). This could be because Sha(E/Q)[2] is nontrivial.
Try increasing descent_second_limit then trying this command again.

sage: x.gens()
RuntimeError: Unable to compute the rank, hence generators, with certainty (lower bound=0, generators found=[]). This could be because Sha(E/Q)[2] is nontrivial.
Try increasing descent_second_limit then trying this command again.

But you can compute the gens of x with a higher descent_second_limit argument:

Comments

Do you mean I can just call the generator(s) by
D=Cremona Database
D.allgens()[]
and use x.padic_regulator or do I then have compute the padic_regulator from there manually (which means there's a string of code that you didn't show)?

I was thinking I should add an answer of my own since it's too long for a comment. I did some digging into the github library files and got the following comment:

# when gens() calls mwrank it passes the command-line
# parameter "-p 100" which helps curves with large
# coefficients and 2-torsion and is otherwise harmless.
# This is pending a more intelligent handling of mwrank
# options in gens() (which is nontrivial since gens() needs
# to parse the output from mwrank and this is seriously
# affected by what parameters the user passes!).
# In fact it would be much better to avoid the mwrank console at
# all for gens() and just use the library. This is in
# progress (see trac #1949).

on lines 1907-1916 of this. So in effect, there is currently no code yet for taking the generators directly from the Cremona Database.

I have very limited knowledge in programming and coding but based on my experimentation so far, this is what I got on SAGE in terms of trying to get the code from the generators in the database:

Then essentially P are the generators that we need, except that they are in the form of a nested list, ie. [[a,b,c],[d,e,f],...] as opposed to when using E.gens() and getting output as [(a : b : c),(d : e : f),...]

With this workaround, I can now obtain padic heights -> the padic height matrix and the discriminant -> padic regulator. Of course this hasn't been written into a proper code yet but it is a workaround.